GPS is the best way to track fleets

The fact that more and more companies are turning to this technology to keep a tab on their vehicles shows that GPS is the best way to track fleets. This can report the speed and location of a vehicle moving in any part of the globe. And what's more there are no regions that GPS signals can’t penetrate, as is the case with cellular services. Concrete jungles or jungles with trees, the GPS can work anywhere.

Among the advantages that a GPS tracking system brings are:

1. Cuts labor costs: Drivers of vehicles usually write their own logs voluntarily. There is no way to authenticate the entries. With a GPS system, the logbooks are replaced by precise reports downloaded directly from the computer. This report has all the details right from when the journey began and where it ended to how many stops were made midway and for what duration. All overtime and other such costs can thus be verified and misuse curtailed.
2. Increases fleet efficiency: The GPS provides full information on the number of service or non-service stops that a particular vehicle or fleet makes. It also gives information on how long a service call or an installation took. This data can be compiled and analyzed to arrive at more productive approaches and cut down on wastage.
3. Helps lower fuel bills: The GPS tracking system is a sure way to cut down on high fuel bills that result from over speeding, unnecessary idling or unauthorized use. GPS tracking captures all such data allowing fleet managers to take necessary steps and precautions. A check on speeding alone results in several benefits. There is a reduction in maintenance costs, gas mileage improves, and accident chances are minimized.
4. Helps control moonlighting of employees: Employees very often tend to use company vehicles for moonlighting or personal use. No one is usually any wiser for it. However, a GPS tracking system discourages drivers from attempting any unauthorized use of vehicles. In the long run this translates into profitability for the organization.
5. Ensures vehicle and cargo security: Every year cargo worth billions is lost in transit. GPS tracking systems play a major role in preventing both vehicle and cargo thefts as well as helping in recovery through better monitoring.
6. Resolve billing disputes: Since the GPS tracking system records the arrival and departure time, to and from a customer address, there can be no discrepancies about the amount of time to be billed.
   

GPS cell phone tracking and privacy issues

The mobile phone technology may have made communication easier but it has also created new problems. At stake is GPS cell phone tracking and privacy issues. No one would like a third party to track his or her movements.

It was not that this was not possible earlier. But earlier the technology was not so perfect or accurate. The cell phones would continue to broadcast a radio signal even when they were not in use, and cell companies could estimate the user’s location through the triangulation method. However, this was a tedious process and a waste of time for cell companies which got no benefit from such tracking.

But now with GPS devices loaded in most cell phones, the location of anyone can be accurately tracked at all times. This has, of course brought several advantages. Some of these are:

• Business owners and fleet managers can keep track of their vehicle movements.
• Police and hospital services can locate the accident spot moments after receiving the call, and save precious lives.
• Individuals can use their cell phones to locate a place, find an alternative route when lost and even relay information about your ETA to their relatives or children.
• Cell phone GPS tracking can also be used to locate children and elderly relatives in a hurry, in case they need urgent assistance.
  

These are all big advantages. But there is a flip side too. No one who is carrying a GPS phone can be away from the eyes of the Big Brother. The tracking can be 24 hours from a remote spot without the user aware of what is being done.

The government has tried to restrict the damage that such technology can cause. That is why it allows carriers to provide tracking information to third parties for e911 emergency calls only; for all other requirements it requires the consent as well as awareness of the cell phone owner.

Even the courts have been firm about the issue. They have flatly refused to allow law enforcement agencies to obtain GPS tracking information from cell phone companies. The information is allowed only when the agencies provide clinching evidence that such tracking will be useful in resolving a criminal case or it is in the interest of the country.

This is good news for the ordinary citizen because it ensures that the advantages pf GPS tracking will not be overshadowed by privacy issues.

GPS applications are many and varied

The GPS applications are wide and varied. They are used from guiding commercial planes and military missiles to helping civilians find their destinations. Some of the important GPS applications are:

1. Military Applications: The Global Positioning System was developed primarily for military use because it enables far-flung military units to know each other’s position with pinpoint accuracy. It helps to spot Target or Cruise missiles accurately especially the submarine launched nuclear missiles. The satellites that form a part of the GPS also carry nuclear detonation detectors and make important contributions to the United States Nuclear Detonation Detection System.
2. Navigation: People across the world use GPS as a navigational aid, both for surface transport as well as air traffic. Mountaineers and hikers use this system to stay better connected and decrease chances of getting lost in wilderness. Glider pilots use them to verify their turn points and many people use low-cost GPA handsets in combination with PDA, car computers or vehicle tracking system.
3. Surveying: GPS plays an important part in land development. It helps to locate boundaries, structures, and survey markers, and provides an accurate topography of the land.
4. GPS for the visually impaired: The GPS is used to help the visually impaired too. Some of the programs that are currently being used for this purpose are: MoBIC, Drishti, Brunel Navigation System for the Blind, NOPPA, BrailleNote GPS, and Trekker.
5. Geocaching: Functionality is not the only facet of GPS. There is now a popular recreational activity called geocaching, which involves using a handheld GPS device to reach a specific latitude and longitude and look for objects hidden there by other geocachers. Most people either hike or walk to the location, increasing the fun aspect of the activity.
6. GPS on airplanes: Planes use GPS to track their flight paths. Most even allow passengers to carry ordinary GPS handsets so that they can track the flight path themselves. In fact some airlines also integrate their GPS systems with the seat back TVs on their flight so that the passengers can keep track of their location at any point of time. Some airlines, however, do not let the handsets aboard their flight because they do not want ordinary passengers to track the flight route.
7. GPS and time: Besides providing accurate location, GPS also provides an extremely precise time reference for the likes of time code generators or NTP clocks. When deploying sensors for any sort of monitoring application, GPS is usually used to provide each recording apparatus with a precise time source, so that the time of events may be recorded accurately.
   

Magellan has a footprint both in US and Europe

Magellan, which is the consumer products brand of Thales Navigation, is one of the world's leading developers and manufacturers of GPS devices and guidance equipment. The company is relatively young having been founded in 1986. However, its products are in great demand across US and Europe.

Magellan increased its range of GPS products when it acquired Ashtech, a leader in the professional GPS category, in 1997. Following the merger Magellan Systems came to be known as Magellan Corporation. In 2001, Magellan Corporation was acquired by Thales, an electronics company with a significant presence defense, aerospace and information technology.

The following are the more popular products that Magellan makes:

1. Magellan RoadMate series: This is a very useful navigation device for Europeans. The customers get a GPS navigation and on-the-go multimedia, full color touch screen, pre-loaded detailed maps of European countries, 3D bird's eye map view, automatic re-route calculation, smart detour routes and route optimization and a built-in music player and photo viewer.
2. Magellan eXplorist series for North America: This product has been developed for North America. It has a color backlit display, unlimited memory using optional secure digital cards, large color screen and high-speed USB data port to quickly download maps or data. Some of the devices in this series have built-in maps, electronic 2-axis compass, barometric pressure altimeter, barometer, and thermometer, and built-in Geocaching application.
3. Magellan eXplorist XL Europe series: This GPS device has been created for Europeans and consists of a large color screen in a rugged GPS handheld, extra large color backlit display, 30 MB internal memory and unlimited memory using optional secure digital (SD) cards for downloading.
4. Meridian series: The Meridian devices have full color display, unlimited memory expandability, 16 MB built-in maps in a rugged, waterproof handheld GPS receiver.
5. Maps and Software: Magellan also provides detailed maps from MapSend to make GPS navigation easier.
   

All these products have made Magellan a major player in the GPS market. The company, however, does not take its position lightly. It continues to innovate, and keeps upgrading its products. The company’s sales team is backed by a highly efficient customer service team which makes sure that Magellan’s customers are satisfied.

Techniques to improve GPS accuracy

There are several techniques to improve GPS accuracy. These include:

1. Differental GPS or DGPS: This can pare down a normal 4-20 meter GPS location to about 1-3 meters. The system uses a series of stationary GPS receivers and calculates the difference between their actual positions and the position calculated by these handsets as per the signal received. This difference is then sent as a local FM signal that the civilians use to get more accurate readings.
2. Wide Area Augmentation System or WAAS: In this system, there are a series of ground stations that calculate GPS errors and upload them to additional satellites that have been put up. These satellites then transmit these corrections to GPS receivers. Since this system uses additional satellites and there are not many available, the method is not widely used. However, WAAS is seen to have tremendous potential and it is assumed that in the years to come the system can also be used reliably for critical applications like GPS-based instrument landing for planes. Variants of the WAAS system are being developed in Europe and in Japan.
3. Local Area Augmentation System or LAAS: This system is similar to WAAS, and uses correctional data. The only difference is that the data is broadcast from a local source, which can be an airport or any other place that requires accurate positioning. The data that is broadcast can only be used within 50 km of transmission.
4. CPGPS or Carrier-Phase Enhancement: This is a correctional technique that uses the 1.575 GHz L1 carrier wave and makes it act like a clock signal. This resolves the discrepancies to an astonishing 20-30 cm.
5. Wide Area GPS Enhancement (WAGE): This system tries to improve GPS accuracy by providing more accurate satellite clock and orbital data to specially-equipped receivers.
6. Relative Kinematic Positioning (RKP): This is yet another GPS-based positioning system. Here the range signal can be fixed with an accuracy of less than 10 cm. This is done by arriving at the number of cycles in which the signal is transmitted and received by the receiver.
   

Finally, at the most basic level, many automobile GPS systems combine GPS units with a gyroscope and a speedometer pick up. This allows the computers to maintain their own navigation when GPS signals are blocked.

Characteristics of GPS receivers

The GPS technology may not be very old but already the market is flooded by several kinds of GPS receivers. These include: the Standalone GPS receivers, Bluetooth GPS receivers, Compact Flash GPS expansion cards and Combo devices. Each has its own characteristics and needs to be understood, before making a purchase.

1. Bluetooth GPS receiver: The Bluetooth GPS receiver needs a PDA, laptop or even a Smartphone to display routes and maps. This is because the receiver does not have a display screen, and can work in unison with another device, provided the display device is loaded with the requisite software. But it delivers good results, and is increasingly becoming popular with the tech-savvy generation since it can interface with different types of Bluetooth-enabled computers and provide high quality voice directions, color screens and color maps. It is ideal for steering and driving instructions, but not for cross-country hiking.
2. Standalone GPS receiver: The standalone GPS receivers are available in diverse shapes and sizes and range from the basic monochrome screen types to full-color handheld and car navigation systems. They are built to work in tough and trying conditions. Being water resistant, they can be used during hiking expeditions and in water sports like sailing. They can also be used for activities like jogging and cycling. A strong point of these receivers is that they can be used to monitor time, distance, speed and heart rate. This makes them very useful for people who want to shed weight or improve their fitness. The first thing that you need to check while buying a standalone GPS receiver is its memory. Receivers with 1 MB to 4 MB memory capacity are of little use because the majority of maps take up from 2 MB to 5 MB of space.
3. Compact Flash GPS expansion cards: These cards were very popular before the arrival of Bluetooth GPS receivers. They could be plugged into the Compact Flash card slots on handhelds and notebook computers. They also did not cost much, and could perform most of the functions that Bluetooth receivers could do. Their only limitation was availability of card-compatible devices. They could work with only those devices that had a Compact Flash slot. The positive side was that they worked very well with PDAs, especially when the aerial pointed skywards. The popularity of GPS expansion cards has been going down in recent days.
4. Combo devices: Several manufacturers, like Mitac, Holux and even Garmin, have introduced GPS chipsets for devices like Pocket PC. This makes these devices similar to standalone GPS receivers but more versatile. They can be used as a personal diary as well as a GPS receiver.
   

You will find a bit of Trimble in most navigation devices

Trimble Navigation Limited is a GPS technology company that integrates a wide range of positioning technologies such as laser, optical and inertial technologies to produce several useful products. Most of Trimble products enable customers to collect, manage and analyze complex information faster.

Today, Trimble products are popular in more than 100 countries around the world. It has 2,400 employees spread across 18 countries, and a network of dealers and distribution partners to serve and support the customers. It is indeed a long way the company has come since the time Charlie Trimble and two other founders established it in 1978.

The company began by focusing on marine navigation. But soon the GPS technology caught Charlie Trimble’s visionary eye and he purchased an evolving GPS technology from Hewlett Packard with the intention of using it for enhanced navigation in all spheres. After this, there was no looking back. The company unleashed a range of GPS products that revolutionized the use of commercial, consumer and military applications.

Trimble was also responsible for taking GPS out of the military camps and making it useful for the common man. For over 25 years now, Trimble has created unique positioning products that help customers grow their business. Its portfolio includes over 700 patents and serves as the basis for the broadest positioning offerings in the industry. Trimble augments its product development with strategic acquisitions so as to stay ahead of competition.

Trimble was among the first companies to integrate GPS technology with communications technology. This enabled users to precisely locate anything on the face of the earth and also share information and messages. It is no surprise to find Trimble products in cars, airplanes, construction equipment, farm machinery, laptop computers, personal digital assistants (PDAs) and more. Its products are also market leaders in the field of oil-drilling surveys, marine navigation applications and software mapping.

Besides this, Trimble's Inmarsat-C GPS system enables long-haul trucks and ships to keep in touch with home, share forecasts about arrival times, and coordinate critically-timed cargo handoffs.

Today after several mergers, buy off and corporate evolutions one thing about Trimble still remains the same -- and that is its focus on cutting edge technology and its ability to be innovative. Whether it is the dispatch and tracking of emergency vehicles, survey or building of roads, mapping of earthquake damage or recording of international financial transactions, there's a bit of Trimble every where.

Navman can guide you to any destination

Navman began in a garage in Auckland as Talon Technology. It soon went on to become an original design manufacturer, adding chart plotters and fish-finders to its existing range of marine instruments such as wind and depth gauges.

It was only in the nineties that the company came to be known as Navman, the name taken from the world's first chart plotters. This was also the time when the company decided to focus on GPS and expanded its portfolio to launch the first portable in-car navigation device in 1997.

The company expanded further in 2001 by acquiring the Rockwell/Conexant GPS module business. This unit became Navman’s commercial GPS solutions arm, and focused on off-the-shelf GPS solutions, private label products, as well as custom solutions.

The company moved quickly in the GPS field and came up with several innovative products. The first was the PDA-based in-car navigation device that was launched in 1997. It soon went on to produce the first mass marketed portable in-car navigation device, the iCN 630, in 2003. That's not all. It also developed the world's first integrated GPRS and GPS receivers that enabled businesses to manage their fleet more efficiently than before.

Simultaneously, the company expanded its presence, and set up units in New Zealand, US , UK, Chile, Denmark, Spain and South East Asia. Today Navman products are available across the globe.

Some of the more well known Navman products are:

1. iCN 520: This is a pocket sized, fully mobile, in-car GPS Navigation System that has a pre-powered rechargeable battery.
2. iCN 550: This incorporates the Navman SmartST 2005 software and comes preloaded with maps of US, Canada, Puerto Rico, and Guam.
3. PiN 570: A personal interactive navigation system it comes with maps of US and Canada. It also has an integrated GPS receiver and full Microsoft Pocket PC functionality and performance.
   

At the heart of Navman products is the GPS receiver. It is the job of this receiver to locate three of the 27 satellites that are used for navigation. Normally, a GPS receiver takes 5 to 15 minutes to track the satellites. It then fixes the user’s position within accuracy of 5 meters or 15 feet.

The receiver can then plot your route, and guide you to your destination. The Navman computer, depending on the model, stores 2 to 5 million points of interest like gas stations, restaurants etc. You are therefore always aware of your next gas station, school or restaurant.

Types of GPS vehicle tracking systems

There are three basic types of GPS vehicle tracking systems. These are:

1. Cellular based tracking systems: A cellular based tracking system transmits the whereabouts of a vehicle every five minutes over a terrestrial network. The initial cost of setting up the system is about $500 while the monthly cost is about $35. This system is especially useful as a safeguard against theft.
2. Wireless passive tracking: These systems simply store information like location, speed and heading. The data needs to be downloaded to a computer at the end of the journey and then evaluated. The disadvantage of such a system is that there is no real time information available and therefore it is not really tracking in the intended sense of the word. You can know where the vehicle had been, not where it is, and that too when it returns to base. Therefore in scenarios like mishaps or thefts, having a wireless passive tracking system is of no use. No one will know where the car is. However, many systems are now attaching wireless modems into their passive tracking devices. With this, the tracking information can be viewed on a computer live. The tracker can learn the vehicle speed, stops or location. This type of tracking system has a one time cost, which is the cost of the system. There are no monthly fees or recurring costs.
3. Satellite based real-time tracking: A satellite based tracking system is a good, no nonsense vehicle tracking solution for shipping and trucking companies. It provides less detailed information but works across the nation. The average cost for setting up the system is about $700. The monthly fees starts from about five dollars and can go up to one hundred dollars, based on how detailed the company wants the reports to be. In the near future GPS based tracking systems will provide customers with other benefits too. Some companies already have a provision where the customer can sign and run credit cards onsite through the unit. Some others are trying to create methods by which directions from a central unit can be sent directly to the drivers’ GPS unit, helping him to re-route if needed. Some GPS systems will have internet access so that in case of a breakdown a driver or mechanic can use the GPS unit as an instruction manual complete to fix the vehicle.

Never ignore geocaching essentials

If you want to hone your GPS skills and have fun on the run, you need to know the geocaching essentials. What you must understand is that geocaching is basically a treasure hunt. In the olden days you would have used maps, compasses and telltale signs to find the booty; with geocaching you use a GPS unit.

Someone hides a cache somewhere and puts up the co-ordinates on his or her website. You just download these coordinates, arm yourself with a GPS unit, and set out to find the goodies. Typically the cache is a weatherproof container such as a Tupperware box or an old army ammunition case. There is a logbook inside and plenty of small little odds and ends.

When you set out to geocache it's a tradition to carry a small gift: a pencil, a small toy, a key chain or even a pin. This is because when you do find the cache, you are supposed to sign in the log book and exchange trinkets from the cache with the ones you bought.

This way there's always something for the person who comes in after you. The only item you should not leave behind is food because there is no knowing when the next geocacher will find it.

In the tradition of the great treasure hunts of yore, the geocache hider may also plant a few clues to make it easier for you. This is because your handset will take you, at best, within a 10 meter radius of the cache. You still need to know where the cache is in that 10 meter radius.

This is where the hints that the hiders gives you come in handy. You will need to decipher them to be able to understand whether it is in the hole of a tree in the earmarked area or under a flowerbed. So if junior is particularly good at solving riddles, he may be a good person to geocache with.

While downloading the coordinates make sure that they do not lead up to a private property or a hazardous zone. If you are geocaching with your family, or even otherwise, you would not want to be at peril. A good geocache hider usually has a list of instructions, which clearly state the dos and the don'ts. It prepares you for what to expect. But if at the end of it all, a cop does show up, the hider is not liable to bail you out.

And finally when you have done enough of finding, you may want to do the hiding. Just remember it is absolutely imperative that you hide the cache in a non-controversial area so that the finders are never inconvenienced. Hide it under a rock at the precipice of the cliff by all means, but make sure that you have given a hint to that effect on your website. And never ever hide a cache in a private property without permission.

Vehicle tracking system has made life easy for fleet owners

A vehicle tracking system is very useful for large corporations that have fleets of vehicles moving across distant areas. The shipping industry has a similar tracking system that it uses to keep track of ships on the high seas. Even ordinary cars nowadays are equipped with this to discourage theft and aid in retrieval. The police can simply follow the signal emitted by the tracking system and locate the stolen vehicle.

Most vehicle tracking systems are basically electronic devices that are installed in vehicles and allow the drivers or third parties to track the location of a vehicle. These devices use GPS modules for easy and accurate tracking of vehicles. Many do not even require the GPS antenna to be in direct line of sight with the sky.

Some systems also combine a cellular or a satellite transmitter so that there can be communication between the vehicle and the remote user. The latter can view the vehicle's information on an electronic map via the Internet or specialized software.

There are two major vehicle tracking devices: passive and active. The passive devices collect data for later analysis. They simply store information like GPS location, speed and heading. The data can be downloaded to a computer at the end of the journey and evaluated. This system does not work well for commercial vehicles where there is a need to monitor vehicles while they are on the move. Two companies that offer passive vehicle tracking devices are TrackStick and TravelEyes.

Active devices, on the other hand, are operational at all points of time. They collect the same data as the passive systems but what they do additionally is transmit them real time via a cellular or a satellite network to a data centre for evaluation. The centre can monitor the vehicle and in some cases even maintain communication with it. Examples of companies that offer active devices are TrackYourTruck and Verizon Wireless.

This system’s potential as an anti-theft device has now resulted in it being made an integrated part of the multi-layered approach to vehicle protection, recommended by the National Insurance Crime Bureau. The Crime Bureau claims that it is very effective in letting the police track the vehicle.

Some of these systems can be integrated with other systems; for instance, an automatic alert to a phone or email can be sent if an alarm is triggered off or the vehicle is moved without authorization.

Garmin has several first to its name in the GPS market

Garmin International Inc is a member of the Garmin group of companies that designs, manufactures and markets navigation equipment both for the aviation industry as well as for the common man.

The company began operations in 1989 with just a handful of engineers and a great product idea. The idea worked and the US army used the Garmin handsets in the 1992 Gulf War. After that, there was no looking back for the company.

Today, its handsets are used by millions of people across the world in fields as diverse as aviation, marine, automotive, wireless, and general recreation. One reason for Garmin’s phenomenal success has been its innovative products, which have made life easier for the common man.

Another reason has been the ease of use. The Garmin systems have logical menus and smart features. This makes it easy to understand their working. Garmin also provides you with easy-to-understand instructional manuals.

Garmin’s constant quest for new products has brought it several firsts. These include: the first non-precision approach using a general aviation GPS, the first multi-function display, the first FRS/GMRS radio and GPS handheld, the first palm-sized GPS/VHF and the world's smallest GPS for the outdoor enthusiast.

Garmin was also the first to design a portable GPS with a moving map. Besides this, Garmin produced a panel-mounted GPS with internal backup battery, a portable/panel mount that interfaces with autopilot and the fully-portable color aviation GPS. Garmin has also been the market leader in sales of aviation transponders, aviation audio panels, panel mount aviation GPS and portable aviation GPS

The Garmin handsets locate satellite signals quickly and track the user’s location wherever they go. The GPS receivers also provide instant updates, smooth scrolling, and real-time moving map capabilities – all this is done in real time and with a great deal of accuracy, quality, and reliability.

Garmin also believes in quality customer service. Its website answers most of the questions that new users may ask; also, its sales are backed by a customer hotline. Garmin believes in customer satisfaction and its staff members spend hours poring over customer complaints and suggestions.

It is therefore not a surprise to see Garmin forging ahead in the world of GPS devices. It continues to introduce new products and upgrade existing ones. This has made it one of the most important players in the GPS market.

A few tips for new GPS users

You need to be patient if you are new to GPS devices. Don’t jump to conclusions, and don’t let your GPS devices drive you. It takes time to master the GPS devices.

Here are a few tips for new GPS users:

• Your GPS receiver needs time to locate satellites before calculating your initial location. The delay is more if you’re changing directions or passing through areas that can obstruct signals. It is always advisable to wait in an open area till you get the satellite signal.
• Once the initial location is found you should set waypoints for your home and other key locations. Familiar waypoints on the map make it easier to stay oriented as you drive.
• Check your speedometer for accuracy. If your speedometer and GPS don't tally trust your GPS. It is more accurate.
• Ask for directions while driving in an unfamiliar part of town. The latest subdivisions and office parks are often missed out on GPS maps. So drive to the nearest crossing and get directions from there. Set a waypoint once you arrive to make it easy for future navigation.
• Focus more on your driving and less on your GPS, even though it’s fun to use.
• Don't let your GPS bully you if it calculates routes you'd rather skip. Be firm and take the road you want-(it will recalculate.) If need be, override your GPS by using the option called "custom avoid" to skip specific areas.
• Watch the satellite status screen to find out how sensitive your navigation system is to GPS signal obstructions.
• Freestanding buildings aren't a problem but if they are built close together the GPS signal gets lost. Systems with ‘dead reckoning’ capacities are more adept at getting reception from the satellite in these conditions.
• You can navigate in and out of a garage parking without taking the help of your GPS but sometimes your navigation system may take a while to figure out where it is after you leave. To overcome this, if you are home wait for some time in the driveway to allow your navigation system to locate the satellite though this may not be possible if you are driving out of a public garage. You may find yourself without a GPS signal for a minute or two if you are driving around.
• Tunnels are another obstacle that tend to block GPS signals but this is a short-lived problem as you can usually regain the signal at or even before your next turn.
• Lastly, the dashboard is an attractive target for thieves so protect your GPS under a handy cloth or cap.
  

How you should go about selecting a GPS device

There are several points that must be kept in mind while selecting a GPS device. The most important is the purpose. You must buy a GPS unit that meets your requirements. There is no point to buy a GPS device that can work well as a navigation system in a car but will have very little use for a hiker.

Depending upon the purpose, you can buy the following GPS units:

1. For hiking: The best GPS device for hikers is one that is light, easy to carry, compact, and weather resistant. Ideally it should be handheld and should have WAAS that is Wide Area Augmentation System. This boosts the GPS accuracy to 10 feet. It should be able to give you readings regarding your location, elevation above sea level, time, satellite location and signal strength. It should also enable you to calculate the distance that you have traveled; record your path as a set of waypoints; and give you the ability to retrace your route. It should also allow you to upload maps and data from your PC. If possible, you should go for a GPS that has 12 channels to catch satellite signals in forests and hilly areas.
2. For jogging and physical fitness: The GPS device should be able to indicate speed, distance, heart rate and time. It should have a computer interface that allows loading of maps and new fitness schedules. It should be shock resistant and weather proof.
3. For driving: While choosing a GPS for your car you can select a handheld GPS device, a fixed GPS navigation system or a PDA. The features to look out for are: street mapping, large display screen, computer interface and external antenna compatibility. A fixed system will have more features and will be more rugged as compared to a portable device. Another downside of a portable system is that the voice instructions are often lost if the car’s music system is running.
4. For boating and other marine applications: The GPS device in this case should have features like: marine mapping, active sonar tracking, back tracking, computer interface and waterproofing.
   

Your next step should be to examine the products available in the market. For instance, if you want to buy a GPS unit as a hiking companion then you should compare the features of different hiking GPS devices. Select the one that meets your need – from the point of view of features and price.

How GPS works

To understand how a GPS works it is important to first see what the system is made of. Essentially a Global Positioning System has three units: a constellation of satellites, a monitoring system and finally, a GPS handset.

The satellites (presently there are 29) orbit the earth at various pre-determined planes, transmitting ranging signals on two frequencies in the microwave part of the radio spectrum. They circle the earth twice daily at an altitude of 20,000 km above earth's surface and have the whole planet in their range.

Now, at any point of time, if a GPS receiver is switched on, it picks up the unique digital code sequences that the satellites continuously transmit. It matches the sequence picked with the ones generated by itself. By thus matching the signals, the GPS receiver is able to calculate how long it takes the signals to travel from the satellite to the receiver. The time is then converted to distance using the speed of light. This is because light and radio waves travel at the same speed.

The receiver is thus able to determine the distance and the location at which the four, or more satellites that it has picked signals from, are placed. This data helps the receiver to calculate its own longitude, latitude and altitude and also to synchronize its time with the GPS time standard.
This process of deducing one's position based on distance measurements is called trilateration and forms the basis of GPS .

This system is for civilian as well as military use and is controlled by a joint board in the US. It is, however, maintained by the US Air Force. The signals that are transmitted for civilians is different from the ones used by the military.

The civil GPS receivers can access the C/A – code which is the coarse/acquisition code transmitted on the L1 frequency. The military has an additional code called the P or the Precision code. This is transmitted on L1 and L2 frequencies. The military usually picks up the C/A code and then transfers it to the P code. There are some receivers, which can access the P-code directly.

It is important to note that GPS receivers do not transmit or bounce signals off the satellites; they simply receive the signals passively. This helps the satellites support an unlimited number of users, both military and civilian. The US Department of Defense that runs the satellites does not levy any fees from the civilian users.

An Automotive Navigation System can guide you to your destination

Automotive navigation system is a satellite-based navigation system that has been designed exclusively for automobiles. This system is different from other GPS systems because it uses position data to specify the location on the unit's map database. It can additionally direct users to areas that are side roads stored in the system's own database.

The first automobile navigation system, designed by Honda, came up in 1983. The system went on to become a general feature in the 1990 version of Acura Legend. This system was a nascent one in which an accelerometer was used to judge locations since the GPS was not yet available for general use. Later in 1990, Pioneer claimed to be the first to bring out a GPS-based auto navigation system.

Most navigation systems in automobiles use a combination of the following elements:

• Top view of the map with the map rotating like the automobile
• Bird's-eye view of the next curve
• Linear gauge for distance( redundant, if a rotating map is used)
• Numbers for distance
  

The road data base that this system uses is basically a vector map of a specific area. All names and addresses and points of interest of the area are encoded as geographical co-ordinates. The user can find them all just by the street address. The database is continuously updated, via the internet, as the person drives from one area to another.

This database can be stored in physical read-only memory (ROM), optical media (CD or DVD), solid-state flash memory, magnetic media (hard disk), or a combination of these. A common practice is to have a base map permanently stored in the ROM, which can then be enhanced with detailed information of a region that the user is interested in. A ROM comes programmed from the factory; the other media may be pre-programmed, or downloaded from a CD or DVD via a computer.

The formats used in this system are proprietary because there is no industry standard for satellite navigation maps. There two map vendors, Tele Atlas and NAVTEQ, create the base maps in a standard format GDF. Each electronics manufacturer thereafter compiles it in an optimized format.

Many automobile navigation systems do more than help users find locations. They give information on services such as restaurants, cash machines and gas stations that may be nearby. Newer systems also receive and display information on traffic jams and suggest alternate routes. Color LCD screens on some navigation systems also double up as TV or DVD screens. A few systems go as far as integrating with mobile phones for hands free talking and SMS messaging.

The popular automobile navigation systems available today are: Etak, Garmin Street Pilot, Gizmondo, Hertz Neverlost, Navman iCN Series, Nextel TeleNav, Tom Tom and Pioneer.

It’s important to be conversant with basic GPS skills

The basic GPS skills that every user needs to master before buying a handset are:

1. How to enter a waypoint: There can be nothing more tedious than punching waypoints one by one, manually. A better option is to either use a full keyboard or just copy paste from a website and then upload. You can also extract or download waypoints you have recorded on your journey and print them directly on a map. This will require software specific to your GPS.
2. Learn how to determine your position: Map reading is an important part of determining your position; the more detailed the map the more specific will be your reading. You can either use the internal map in the GPS handset to understand your location or you may do so by recording waypoints and then using an external map. If your handset shows maps, chances are it has simple maps loaded in it because of memory constraints. You can upload detailed maps, but you would need software specific to your brand of GPS and, you will need plenty of memory. The maps that your find in Garmin's MapSource are functional but they are definitely not detailed. National Geographic has map software called TOPO that provides excellent topographic maps. But unfortunately these cannot be uploaded into GPS units because these units are not compatible with third-party maps. But there's a way out: use Gramin's software to download the recordings you made in the field; then transfer these coordinates to the National Geographic's software to produce a detailed map for your travel. The good thing is that National Geographic offers TOPO CDs by the state. So you only need to buy the CD you need. This makes TOPO quite inexpensive. You can also try packages for road maps such as DeLorme.
3. Learn how to navigate: If you're a new GPS user you must remember one thing: your handset is not like a traditional compass. You need to be moving for the GPS to help you. Begin by choosing your destination waypoint so that the unit knows which direction to look in; then simply start walking so that the system's navigation feature gets activated. Along with location there are other interesting things that your unit can throw up. It can give you your altitude, the distance traveled, your speed and the track that you took.
   

What is GPS

The Global Positioning System, or GPS as it is popularly known, is a satellite aided navigation system that was first developed by the United States Department of Defence.

As the name suggests, the system helps in pinpointing the exact location of moving or stationary objects anywhere in the world.

The position coordinates are obtained with the help of 24 satellites that beam down precise signals through radio to GPS receivers all over the world. This helps the receivers to find their location in terms of longitude, latitude and altitude, with great accuracy, irrespective of weather conditions.

Behind this seemingly simple function is a $400 million annual investment of the US Department of Defense. The department maintains all the satellites that make this system possible. The actual coordination is done by the 50th Space Wing based at Schriever Air Force Base. This wing has its hands full making sure that all the satellites work in tandem and are accurate to the last micro second.

Besides this, there are five monitoring stations located at Hawaii, Kwajalein, Ascension Island, Diego Garcia and Colorado Springs. They report to the master control station which is at Schriever AFB. Interestingly, the US government makes the system available free of cost for civilian use.

The system itself has been designed very carefully. It has 24 satellites that have been put up in space in six orbital planes. Each plane has four satellites, each in its own orbit. The positioning has been done in such a manner that at any point of time, no matter where you are on this planet, there will be four satellites in your line of vision. These satellites circle the Earth twice daily at an altitude of 20,200 kilometres and send down packets of information.

These packets include information about their orbital position, and an almanac of the approximate position of every other active GPS satellite. The almanac lets GPS receivers use this data from the strongest satellite signal to locate other satellites. After that the receiving set does a series of calculations using the concept of trilateration and throws up the exact location.

The popularity of GPS can be gauged from the fact that it being used in all modern forms of navigation -- ships, planes and surface transport. The system also helps in land surveys and cartography besides being an extremely precise time reference for telecommunications and scientific research.

In fact, in the latter part of 2005, a series of next-generation satellites were added to the existing group. These satellites had a second civilian GPS signal called L2C for enhanced accuracy. In the years to come the satellites that will go up will add the third and fourth civilian signal.